Yemeni pro-government forces, backed by the United Arab Emirates, are reported to have stormed the airport serving the rebel-held Red Sea city of Hudaydah.
The UAE's state news agency, Wam, said troops had gained control of large parts of the facility and that dozens of Houthi rebels were dead or wounded.
They launched a major offensive last week to capture the city and its port.
The port is crucial to the delivery of aid supplies to Yemen, where 8.4 million people are at risk of famine.
There are grave fears that the fighting will disrupt the flow of this humanitarian assistance.
Yemen has been devastated by a conflict that escalated in early 2015, when the Houthis seized control of much of the west of the country, including the capital Sanaa, and forced President Abdrabbuh Mansour Hadi to flee abroad.
Alarmed by the rise of a group they saw as an Iranian proxy, the UAE, Saudi Arabia and seven other Arab states intervened in an attempt to restore the government.
Almost 10,000 people – two-thirds of them civilians – have been killed and 55,000 others injured in the fighting, according to the United Nations.
The coalition says the Houthis have used Hudaydah's port to receive weapons smuggled by Iran – an allegation both Tehran and rebel leaders have denied.
Wam reported on Tuesday that Yemeni and Emirati troops…